Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantas segundas pernas tiveram um agregado de 2-4?
 ###Tabelas: CREATE TABLE sports_teams (sports_teams_id AUTO_INCREMENT PRIMARY KEY, Sport VARCHAR, League VARCHAR, Club VARCHAR, Founded INT, Venue VARCHAR, League championships INT, Championship years VARCHAR) CREATE TABLE regular_season_and_post-season_games (regular_season_and_post-season_games_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Kicker VARCHAR, Kicking team VARCHAR, Opponent VARCHAR, Yards INT, Result VARCHAR, Game time VARCHAR) CREATE TABLE winners_knockout (winners_knockout_id AUTO_INCREMENT PRIMARY KEY, Home (1st leg) VARCHAR, Home (2nd leg) VARCHAR, 1st Leg VARCHAR, 2nd leg VARCHAR, Aggregate VARCHAR) CREATE TABLE parliaments_of_king_edward_iv (parliaments_of_king_edward_iv_id AUTO_INCREMENT PRIMARY KEY, Summoned VARCHAR, Elected VARCHAR, Assembled VARCHAR, Dissolved VARCHAR, 1st member VARCHAR, 2nd member VARCHAR) CREATE TABLE box_office_score_data (box_office_score_data_id AUTO_INCREMENT PRIMARY KEY, Venue VARCHAR, City VARCHAR, Tickets Sold / Available VARCHAR, Gross Revenue (1982) VARCHAR, Gross Revenue (2011) VARCHAR)  
SELECT COUNT 2nd leg FROM winners_knockout WHERE Aggregate = 2-4